Pump



Nov l, 1949.

D. W. CRISWELL PUMP Filed Jan. 14. 1947 JNVENToR. DHV/D W CH/Swf/ L BY (fa 5M (f /fZ//v romeys Patented Nov. l, 1949 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to improvements in pumps.

A primary object of the invention is to provide an improved compound type pump wherein there is a pair of working cylinders to which the uid to be pumped is admitted and from which it is expelled and wherein the pistons or movable diaphragms in the working cylinders are actuated by a fluid supplied from cross connected actuating cylinders within which pistons are simultaneously reciprocated in opposite directions. By such an arrangement the pistons in the actuating cylinders are isolated from the fluid that is being pumped and if the uid that is being pumped is hot the temperature thereof is not readily conducted to the pistons in the actuating cylinders. Also if the fluid that is being pumped contains a gritty or abrasive material, this material is likewise kept isolated from the actuating cylinder and the piston thereon. Consequently the wear in the actuating cylinders is reduced to a minimum.

The arrangement of the improved pump is such that although the lengths of the strokes in the actuating cylinders is relatively small the strokes of the pistons or diaphragms in the working cylinders are approximately twice that of the actuating pistons which features are highly desirable in certain types of pumping.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a top plan view of the improved Pump;

Fig. 2 is a sectional view taken substantially upon the line 2-2 upon Fig. 1; and

Fig. 3 is a sectional view taken substantially upon the line 3--3 upon Fig. 1.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the improved pump comprises two working cylinders I!) and Il. These cylinders have inlets at I2 and I3 respectively controlled by inlet valves I4 and I5 respectively. 'I'he outlets from these working cylinders are indicated at I6 and I1 respectively and are controlled by outlet valves I8 and I 9. Within the working cylinders there are working pistons or diaphragms 20 and 2l. These pistons or diaphragms are freely slidable within the working cylinders being actuated entirely by uid pressures effective on their faces. As the liquid or iiuid that is being pumped has a relatively high temperature these working pistons or diaphragms that are freely slidable in the working cylinders may be formed of a heat insulating material to reduce conduction of heat from the pumped` liquid to the actuating mechanism.

The actuating mechanism consists of two actuating cylinders 22 and 23. These actuating cylinders are cross connected by suitable conduits indicated at 24 and 25. Thus the forward end of the actuating cylinder communicates directly with the rear end of the working cylinder I i and is connected by the cross connection 24 to the rear end of the actuating cylinder 22. Conversely the forward end of the actuating cylinder 22 is in direct communication with the working cylinder I0 and is cross connected by the cross connection 25 to the rear end of the actuating cylinder 23. Within the actuating cylinders there are actuating pistons 26 and 21. These pistons are reciprocated simultaneously in opposite directions. Any sort of prime mover or driving mechanism which will so drive the pistons 26 and 21 may be employed. For purposes of illustration, however, 4the actuating mechanism consists merely of a driven gear 28 driven by a pinion 29 on a drive shaft 30. This driven gear has oppositely disposed crank pins 3| and 32 that are connected by pitmans 33 and 34 to the piston rods of the pistons 26 and 21.

'I'he cylinders 22 and 23 are filled on both sides of the pistons 26 and 21 with a fluid such as clean oil. During the forward movement of the piston 26 oil in the forward end of the cylinder 22 is forced into the rear end of the working cylinder I0. Simultaneously the piston 21 is moving rearwardly so that oil in the rear end of cylinder 23 is being expelled thereby through the cross connection 25 into the forward end of the cylinder 22 and into the rear end of the working cylinder I0. While the piston 26 is moving forwardly and the piston 21 is moving rearwardly fluid in the rear end of the working cylinder I I is being drawn into the forward end of the actuating cylinder 23 and through the cross connection 24 into the .rear end of cylinder 22. When the direction of strokes of the pistons 26 and 21 is reversed the oil is traveling in the reverse direction to and from the working cylinders I0 and I I and through the cross connections 24 and 25.

With the above arrangement it will be appreciated that with a given length of stroke of the pistons 26 and 21 that the volume of oil forced into the working cylinders behind the working pistons 20 and 2l is such that the length of stroke of the working pistons or diaphragms is substantially doubled. Consequently with a relatively short length of stroke of the actuating pistons the length of strokes of the working pistons is quite long. The working cylinders may or may not be surrounded by water jackets 35 and 36 to which cooling water may be supplied such as through connections 31 to cool the liquid that 'is being pumped in the event that such .liquid has a relatively high temperature. With this arrangement it will be appreciated that the linlet and outlet valves controlling ingress to and egress from the working cylinders can be conveniently located for purposes of ease in removal whenever it is desired to repair or replace these valves. These Valves may be relatively large to reduce friction as fluid flows therethrough in the course of pumping. If the fluid that is being pumped is quite hot as in the case of hot oil, its temperature is not conducted to the working parts of the pump in the actuating cylinders and as the diaphragms or working pistons 2U and 2| isolate the pumped liquid from the oil in the actuating cylinders wear of parts in the actuating cylinders is reduced to a minimum.

From the above-described construction it will be appreciated that an improved pump has been developed which by reason of its compounded construction enables a relatively short actuating stroke to be multiplied into a long working stroke.

Only four valves are required and these may be so located as to be readily accessible.

While the use of the diaphragms or working pistons is preferable there are situations particularly when the pumped liquid is relatively clean where these diaphragms or working pistons may be omitted entirely.

Various changes may be made in the details of construction without departing from the spirit and scope of the invention as dened by the appended claims.

I claim:

1. A pump for pumping hot liquids comprising two parallel horizontal cylinders, each cylinder having a driving piston working in one part thereof and an isolated floating diaphragm working in the other part thereof, means for moving the driving pistons simultaneously in opposite directions, said means being located at one pair of ends of the cylinders, means cross connecting the parts of the cylinders in which the driving pistons work so that on rearward strokes of the piston in one cylinder fluid may ow to the forward end of the other cylinder and vice versa, valve means located at the opposite ends of the cylinders for controlling ingress to and egress of the hot liquid from the parts of the cylinders in which the floating diaphragms work, whereby the heat from the valve ends of the cylinders is not transmitted to the driving ends of the cylinders.

2. A pump as defined in claim 1 in which there are cooling 'means provided around the two parallel horizontal cylinders for cooling the cylinders in the parts thereof wherein the floating diaphragms work.

3. A pump as defined in claim 2 in which the iioating diaphragms are of insulating material whereby transfer of heat from the valve ends of the cylinders through the floating diaphragms to the driving ends of the cylinders is prevented.

DAVID W. CRISWELL.

REFERENCES CITED UNITED STATES PATENTS Name Date Carroll i Dec. 10, 1935 Number 

